Process for treating steel



Patented Jan 22, 1929 UNITED STATES 1,699,683 ATENT OFFICE.

HERMAN a nrnrnne,

OF 1 GINCIN N A'II, OHIO.

' PROCESS FOR TREATING STEEL.

Ho Drawing. Application flied Kay '7,

My invention relates to processes of treating metals adapted for use as high speed cutting tools, and has to do more particularly treat the steel that when used for tools, such lll til

tilt

as machine cutting tools, they have greater wearing qualities, and many other advantages hereinafter more particularly pointed out.

Generally speaking, my improved process consists of heat treating, high speed steel or metal, or metal used for highspeed cuttlng tools so as to improve it in various ways and make it more susceptible to better hardening. To this end, the steel is immersed in a bath of molten metal of such character and temperature, that it acts upon the steel as to improve.

its qualities as stated above, and so far as I am able to observe forms an incrustatlon on the metal which appears when it is withdrawn from the bath.

I have found that high speed steel treated according to my process, produces astonishing results in that there is-less brittleness of the cutting edges of the tool, greater resistance to wear, and extension of the life of the tool, in that less grinding is necessary.

More particularl in employing my proc ess in its preierre form, I provide a bath for the tool in the form of molten lead and preferably add a small portion of copper to revent burning of the lead by reason of the ill igh temperature of the bath.

ll find that seven parts of lead to one part ing tem suficiently to form an alloy. This xture used as a bath is heated from a melting or fusing tem erature of the composition to 1800 degrees ahrenheit tor treatlng the steel. le heating the metal, 1 preferably place a layer oi crushed charcoal over the top, and this must be refreshed or it becomes foul, apparently with the sulphur extracted from the steel bein treated. A slight addition of such alloy 1% charcoal every time the bath s used, will overcome this foul ng dificulty.

l now place the tool oi hlgh speed steel, or the piece to be treated, in the bath so that it is below the surface, avoiding contact of the cutting edges of the tool with the crucible, so that the fluid'ot the bath uniiormly covers the steel,

ct coper, serves the purpose very well, heat" 1923. Serial No. 887,858.

7 I find that the highertemperature reduces a quicker operation in that the bubb ing and incrustation upon the steel "is produced in a shorter period of time, but there is always the danger of the high temperature in that it may possibly absorb some ofthemetalscomprising the various constituents of high speed steel. For this reason a lower temperature is more desirable, and I find that a temperature just above the melting point of the com-" position works very well.

At the high heat treatment, that is closer .to 1800 degrees, I find that after the steel is heated five minutes or so, what apparently is a sulphurous smoke, rises from the steel and accumulates as an incrus'tation on the outside of the steel. At the lower heat treatment, with a tool made up of bar steel one inch by one-half inch, smoke will issue in about ten minutes and the treatment evidently is well completed in about twenty minutes.

I find that it is desirable to drop the temperature of the bath to closely above the fusing point while treatin the steel and before itis removed from the bath. The steel after being removed from the bath and cooled should be cleaned by removing the incrustation on the surface, preferably by using an ordinary scraper or a wire brush. It is then ready to be hardened if required in any of the well known ways. i

I find that when immersing the metal which i is to be treated in the heat bath, the bath will bubble like boiling water, the bubbling varying with difl'erent pieces being iersed. This diflerence in the boiling apparently arises trom difiierences in the amount of undesirable or foreign substances in the metal which isbeing treated.

' Fools when forged and still hot may be placed in the bath, but under such conditions it is desirable that they be below the temperature of the bathso as to avoid placing a contractional strain on the tool, due to the bath acting as a coolin agent. The tools may, however, be place in the bath when cold and left in long enough to complete the treatment by becoming heated through and then soaking for ten minutes or more depending upon the size of the piece bein treated, until a smoke arises from the too and an incrustation terms on the surface when it isremoved from the bath and expo to the air.

What I cla as new and desire to secure by United htates Letters Pat is;

' long enou 1 800 degrees Fa 1. The process of treating cuttin tool metal to make it susceptible to better ardening consisting of immersing a piece of high speed steel or other cuttin bath of substantially seven parts lead and one art co per at a tern erature above fusing of t e bat leaving t e steel in'the 'bat h to have the surface of the iece covered with a sediment formed in the ath, and then gradually cooling the steel after withdrawing it from the bath.

2. The rocess of treating metal to make it susceptl 1e to better hardening consisting of immersing a piece of high speed cuttin tool metal in a molten metal bath of lead an copper at a tem erature of approximately nheit, and saving the piece in the bath sufliciently long enough to assume the temperature of the bath and also have the surface of the piece incrusted with a sediment formed thereby. j

3. The process of treating metal consistin of immersin the metal in a molten meta bath comprising lead and a sufiicient uantity of copper to prevent burning oft e lead 1 while at a temperature suflicient to treat the metal, the temperature of the bath being pref.- erably suflicient to form an incrustatmn on the treated metal, leaving the metal in the metal in a molten metal bath long enough tohave the surface of the piece incrusted with sediment formed during immersion, then cooling the metal and cleaning its surface for furt er desired treatment.

4. The process of treating metal or cutting metals consisting of immersin a iece of high speed cuttin tool metal to be ormed as a tool in a mo ten metal bath comprising approximately seven parts lead and one part copper at a temperature above the fusing temperature of the bath but low enough to prevent absorbing any of the metal constituents of the treated metal, leaving the metal in the bath at least; until a sediment has accumulated on the surface of the metal, and removing it from the bath for desired subsequent treatment.

5. The process of treating high speed steel, which consists of immersing it in a molten bath of substantially seven parts lead and one part copper for a period of time proportional to about twenty minutes for a piece onehalf inch in thickness, at a temperature between the fusing point of the bath and 1800 degrees Fahrenheit.

In; witness whereof, I hereunto subscribe my name this 28th day of April A. D., 1923.

HERMAN J. BIEFAN G. 

